Method of purifying waste fluid

ABSTRACT

A FRONTWARD FLOW AND BACKWARD FLOW METHOD OF AND APPARATUS FOR PURIFYING WASTE FLUID CONTAINING WASTE WATER AND CORROSIVE SALTS WITH A HIGH TEMPERATURE STEAM FROM A CONTINUOUS COKE QUENCHING APPARATUS TO PRODUCE SUBSTANTIALLY PURE SALT FREE CONDENSATE ARE DISCLOSED. (A) ONE METHOD OF PURIFYING WASTE FLUID, CONTAINING WASTE WATER AND CORROSIVE SALTS PRODUCED IN A COKE PRODUCING APPARATUS AND NORMALLY UTILIZED TO QUENCH COKE IN A COKE QUEENCHING APPARATUS, WITH WASTE STEAM FROM THE COKE QUENCHING APPARATUS TO PRODUCE SUBSTANTIALLY SALT FREE CONDENSATE, COMPRISE THE STEPS OF: (A) HEATING THE WASTE FLUID IN HEAT EXCHANGE RELATIONSHIP WITH THE STEAM TO A FIRST PREDETERMINED TEMPERATURE AT A FIRST PREDETERMINED PRESSURE; (B) CONDENSING THE HIGH TEMPERATURE STEAM TO FORM SUBSTANTIALLY SALT FREE CONDENSATE; (C) VAPORIZING THE HEATED WASTE FLUID AT THE FIRST PREDETERMINED TEMPERATURE AT THE FIRST PREDETERMINED PRESSURE TO VAPORIZE A PORTION OF THE WASTE FLUID AND TOCONVENTRATE THE CORROSIVE SALTS TO FORM A CONCENTRATE, THE FIRST PREDETERMINED PRESSURE BEING LOWER THAN THE PRESSURE OF THE WASTE STEAM FROM THE COKE QUENCHING APPARATUS; (D) CONDENSING THE HEATED VAPORIZED PORTION OF THE WASTE FLUID TO FORM SUBSTANTIALLY SALT FREE CONDENSATE IN AN (E) UTILIZING THE SUBSTANTIALLY SALT FREE CONDENSATE IN AN INDUSTRIAL APPLICATION, THEREBY ELIMINATING THE DISPOSAL OF THE WASTE FLUID AND THE CONTAMINATION OF THE ATMOSPHERE WITH THE WASTE FLUID IF THE WASTE FLUID WERE EMPLOYED TO QUENCH THE COKE IN THE COKE QUENCHING APPARATUS, AND UTILIZING THE WASTE STEAM FOR A USEFUL PURPOSE.

Feb. 5, 1974 w.J. DIDYCZ ET AL 3,790,448

METHOD OF PURIFYING WASTE FLUID Filed March 5, 1971 4 Sheets-Sheet 1 FIG,

Flushing L/a uor Feed Line Lg From Collecting Main /6 /2 C LZ fg e,

l7 COKE OVEN L8 32QUENCHER I BATTERY 7'0 Screens Suction- 1 Main) /0 L2 COOLER Return Flushing Z Q'ZZQ EAN Liquor Line From Gas for Underfiring L4 Ca/re Ovens F I v 70 Gas lashing p Liquor L3 recess/n9 Decanter Tank 22 7'0 .SeH/ing Tan/r (FIG. 3/

For Further Processing or Ar forney Feb. 5, 1974 w. DIDYCZ ET AL 3,790,443

METHOD OF PURIFYING WASTE FLUID 4 Sheets-Sheet 4.

Filed March 5, 1971 DONALD GLASS/VAN vm w Attorney United States Patent 3,790,448 METHOD OF PURIFYING WASTE FLUID.

William J. Didycz, Whitehall Borough, and Donald Glassman, Mount Lebanon Township, both of Allegheny County, Pa., assignors to United States Steel Corporation Filed Mar. 3, 1971, Ser. No. 120,540 Int. Cl. B01d 3/06; Cb 39/08 US. Cl. 201-39 13 Claims ABSTRACT OF THE DISCLOSURE (a) heating the waste fluid in heat exchange relationship with the steam to a first predetermined temperature at a first predetermined pressure;

(b) condensing the high temperature steam to form substantially salt free condensate;

3,790,448 Patented Feb. 5, 1974 lCe OBJECTS OF THE INVENTION It is the general object of this invention to avoid and overcome the foregoing and other difiiculties of and objections to prior art practices by the provision of an improved apparatus for and method for purifying waste fluid containing waste water and corrosive salts with waste steam at essentially atmospheric pressure from a continuous coke quenching apparatus to produce substantially pure salt free condensate, which improved apparatus and method:

(a) utilize the heretofore wasted steam from a continuous coke quenching operation to produce the salt free condensate;

(b) .produce substantially salt free condensate for use in boilers or as coke quenching fluid;

(c) eliminate the corrosive atmosphere polluting eflluent produced in coke quenching operations by the use of contaminated waste fluid from the coking operation as a'coke quenching fluid;

(d) eliminate suspended tar particles from the waste (c) vaporizing the heated waste fluid at the first predetermined temperature at the first predetermined pressure to vaporize a portion of the waste fluid and to concentrate the corrosive salts to form a concentrate, the first predetermined pressure being lower than the pressure of the waste steam from the coke quenching apparatus; (d) condensing the heated vaporized portion of the waste fluid to form substantially salt free condensate; and (e) utilizing the substantially salt free condensate in an industrial application, thereby eliminating the disposal of the waste fluid and the contaminationof the atmosphere with the waste fluid if the waste fluid'were employed to quench the coke in the coke quenching apparatus, and utilizing the waste steam for a useful purpose.

BACKGROUND OF THE INVENTION Heretofore, severe atmospheric corrosion of structures, buildings, and process equipment has occurred at coke processing plants for many years. The problem has recently become more critical as a result of the installation of additional chemical processing facilities thus placing a high concentration of complex process equipment in an area exposed to this atmospheric corrosion. A major cause of this problem is the use of aqueous waste streams to quench the coke. These Waste streams contain dissolved inorganic salts that become air-borne with the steam produced in the quenching operation, and subsequently upon cooling, rain out of the atmosphere on adjacent buildings and equipment. Unfortunately, these salts are verycorro-- sive to structures, buildings, and process equipment that are in the path of this salt fallout. This situation has been tolerated because no economically-attractive alternative method of disposing these waste streams was available. Disposal of the aqueous waste streams in a deep well has been considered and is being practiced in some coke plants. However, deep well disposal at some coke processing plants requires a disposal well of about 19,000 feet; and the probability of such a well being able to handle the large volume of water has been reported to be fifty percent. Further, a danger exists that underground streams will be contaminated by this method of waste disposal.

- fluid; (e) eliminate benzene, tar acids, tar bases, and oil from the Waste fluid;

(f) eliminate C0 NH H S and benzene from the waste fluid; and (g) eliminate corrosive salts from the waste fluid.

BRIEF SUMMARY OF THE INVENTION The aforesaid objects of this invention, and other objects which will become apparent as the description proceeds, are achieved by providing an improved (frontward and backward flow) apparatus for and method of purifying waste fluid containing waste water and corrosive salts with waste steam from a coke quenching apparatus to produce substantially pure salt free condensate.

(A) One method of purifying Waste fluid, containing waste water and corrosive salts produced in a coke producing apparatus and normally utilized to quench coke in a coke quenching apparatus, with waste steam from the coke quenching apparatus to produce substantially salt free condensate, comprises the steps of:

(a) heating the waste fluid in heat exchange relationship with the steam to a first predetermined temperature at a first predetermined pressure;

(b) condensing the high temperature steam to form substantially salt free condensate;

(c) vaporizing the heated waste fluid at the first predetermined temperature at the first predetermined pressure to vaporize a portion of the waste fluid and to concentrate the corrosive salts to form a concentrate, the first predetermined pressure being lower than the pressure of the waste steam from the coke quenching apparatus;

(d) condensing the heated vaporized portion of the waste fluid to form substantially salt free condensate; and

(e) utilizing the substantially salt free condensate in an industrial application, thereby eliminating the disposal of the waste fluid and the contamination of the atmosphere with the waste fluid if the waste fluid were employed to quench the 'coke in the coke quenching apparatus, and utilizing the waste steam for a useful purpose.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS For a better understanding of this invention, reference should be had to the accompanying drawings, wherein likenumerals of reference indicate similar parts through the several views and wherein:

FIG. l'is a diagrammatic view of a portion of a coke plant showing the production of raw gas and waste fluid during the coke manufacturing operation;

FIG. 2 is a diagrammatic side elevational view of a continuous rotary coke quenching apparatus showing the production of steam from the coke quenching operation for use in method of and apparatus for purifying the waste fluid from the coke manufacturing operation;

FIG. 3 is a diagrammatic view of one embodiment of the novel apparatus of this invention for purifying the waste fluid from the coke manufacturing operation;

FIG. 4 is a fragmentary diagrammatic view of an alternative embodiment of the first stage of the apparatus shown in FIG. 3 and showing the steam generated in the continuous rotary coke quenching apparatus directly flowing to the first heat exchanger of the first stage of the improved apparatus; and I FIG. 5 is a view similar to FIG. 3 of a further alternative embodiment of the improved and novel apparatus and showing backward flow of the waste fluid through such apparatus.

Although the principles of this invention are broadly applicable to an apparatus for and a method of purifying waste fluid with steam generated from a continuous coke quenching apparatus, this invention is particularly adapted for use in conjunction with apparatus for and a method of purifying waste fluid containing waste water and corrosive salts with steam from a continuous rotary coke quenching apparatus, and hence it has been so illustrated and will be so described.

DETAILED DESCRIPTION With specific reference to the form of this invention illustrated in the drawings and referring particularly to FIG. 1, a battery of coke ovens is indicated generally by the reference numeral 10. a

WASTE FLUID PRODUCTION The battery 10 (FIG. 1) receives mixed coal from a crusher (not shown) as indicated by the line L1. Gas for under-firing the coke ovens is supplied to the battery 10 (FIG. 1) of coke ovens via the line L2. The volatile products from the coal being processed into coke 36 (FIG. 2) within the battery 10 of coke ovens, exists from the battery 10 via ascension pipe 12 (FIG. 1) and goose neck 14, and enters a collecting main 16. This collecting main 16 (FIG. 1) carries the raw gas and condensate to a primary cooler 18.

Such primary cooler 18 may be either of the direct or indirect type. For example, a direct primary cooler (not shown) has a scrubbing tower provided with bafiies and has its top portion equipped with a series of spray nozzles, all not shown. The lower portion of the primary cooler 18 contains a chamber to collect the condensate and liquor.

The cooled gas from primary cooler 18 (FIG. 1) is exhausted by an exhauster, such as a fan 20 or the like, through a suction main L3 and is directed as indicated by the arrow in FIG. 1 to further gas processing and chemical recovery equipment (not shown). The liquor and condensate exit from the primary cooler 18 via a condensate line L4 into a flushing liquor decanter tank 22. This tank 22 is inclined at one end to facilitate the removal of solid accumulations. The tar and flushing liquor enter the decanter 22 and flow into a trough (not shown), which trough is operable to minimize agitation of the mixture in the decanter tank 22. The mixture overflows the trough into the compartment (not shown) where the velocityof the mixture is reduced to permit the tar (having a higher specific gravity than the flushing mixture) to settle to the bottom of the compartment from whence it exits via line L5 to tar storage tanks 24, where it is stored preparatory for further processing or for use as fuel. The flushing liquor flows over a fixed wier at the opposite end of the decanter tank 22 (FIG. 1) and is conducted via line L6 to separation tanks 16 preparatory for its transmission via line L7 to a settling tank 28 (FIG. 3).

The flushing liquor is returned via line L411 (FIG. 1) to the junction of the goose neck 14, the collecting main 16, and a line L4b (FIG. 1) leading to a downcomer 17, which downcomer 17 is connected via a line L4c (FIG. 1) to the flushing liquor decanter tank 22. The liquor which leaves the separation tanks 26 (FIG. 1) is a waste fluid containing waste water and corrosive salts, suspended material and the like, and having, for example, the following approximate composition shown in Table I below.

TABLE I i v; I Coke oven waste fluid Compound: 7 I Lbs/hr. CO: 640 NH;., 461 Water 273,840 X Tar acids (phenol, meta, para cresols, etc.) X Tar bases (quinolins, etc.) 55 X Oil 18 Tar 223 NI-I Cl 1,417

Other salts 304 Norn.Rem0ved by: X benzene extraction; distillation; settling tank, benzene bubbler.

The coke 36 (FIG. 2) is pushed from the battery 10 (FIG. 1) of coke ovens in the conventional manner into quencher cars 30 (FIG. 2) and is transmitted as indicated by the diagrammatic line L8 in FIG. 1 to a quench ing station 32, where a continuous quenching device such as, for example, a continuous rotary quencher 32 (FIG. 2) of the type manufactured by Salem Brosius Company, Pittsburgh, Pa., is employed to quench the coke 36 and to produce the steam utilized in the subject invention.

CONTINUOUS QUENCHER 32 The quencher 32 (FIG. 2) is disposed in a pit 34, substantially below ground level. The coke 36 (FIG. 2) in the quencher car 30 is dumped into a hopper 38, which hopper 38 feeds the coke 36 onto a rotary table 40 where the rabbles 42 spread out the hot coke 36 over the rotating table 40 so that substantially pure quenching fluid (produced by this invention) in line L8 (FIGS. 2, 3) enters sprays 44 for the cooling and/ or quenching of the hot coke 36 on the table 40. This substantially salt-free cooling fluid is supplied by line L8 (FIGS. 2 and 3), which line L8 extends from a distillation tower 46 shown in FIG. 3

" and employed as hereinafter explained.

The quenched coke 36 is conducted via a chute 48 (FIG. 2) onto a conveyor 50, which conveyor 50 transw STEAM PRODUCTION The steam produced from the quenching operation is collected within a hood 56 (FIG. 2) of the continuous rotary quencher 32 and is conducted by a steam line L9 to a steam stack 58. This steam stack 58 has a damper or valve 60 for directing the flow of steam either through the steam stack 58 or through a steam line L10 (FIG. 2) via a. valve 62 to a deentrainment vessel V1 (FIG. 3) of the apparatus 64 (FIG. 3) for purifying the waste fluid in line L7 (FIGS. 1, 3) with the high temperature steam in line L10 (FIGS. 2, 3) from the continuous coke quenching apparatus 32 to produce substantially salt free condensate.

APPARATUS 64 First stage The steam in line L10 (FIGS. 2, 3) at approximately 400 F. and at about 14.1 p.s.i.a. pressure enters the deentrainment vessel V1 (FIG. 3) where coke breeze (i.e., coke particles) is removed by sprays S1. The coke breeze is collected via line L11 (FIG. 3) in a dewatering vessel V4 evaporator EV1.

and fed via line L12 to, for example, a coke wharf (not shown) for further processing. A pump P6a (FIG. '3) pumps Water from the dewatering vessel V4 for the spray S1 via line L13 into the deentrainment vessel V1. The now relatively clean steam (freed of suspended coke breeze) is conducted via line L14 (FIG. 3) at a temperature of about 200 F. to a first heat exchanger E1.

Meanwhile, the waste fluid or liquid in line L7 (FIGS. 1, 3) passes through the settling tank 28 (FIG. 3) where suspended tar particles are removed therefrom; is then bubbled through or contacted with a layer of liquid containing light oil, benzene, or the like in a contacting vessel 66 to remove tar particles which have been suspended in the form of small droplets in the waste fluid; and then through a liquid extraction tower 68 (FIG. 3), where dissolved phenol and other organics in the waste fluid are removed.

It will be noted from a consideration of FIG. 3 that the branch line L15 from line L13 dilutes the waste fluid in line L7 with water pumped thereto by pump P6A. The watered waste fluid enters the tube side of heat exchanger E1 via line L16.

The steam in line L14 (FIG. 3) is sucked into, for example, the shell side of the heat exchanger E1 by a steam jet J1 and the waste fluid in line L7 is pumped into the tube side of the heat exchanger E1 by a pump (not shown). The waste fluid is heated in heat exchange relationship with the steam (at a temperature T0 of about 200 F. and a pressure P0 of about 13.8 p.s.i.a.) in the heat exchanger E1 to a first predetermined temperature T1 of about 186 F. at a first predetermined pressure P1, such as about 8.72 p.s.i.a. The cooled condensate from the steam in heat exchanger E1 exits therefrom via line L17 (FIG. 3) through a steam trap STl and is collected in a condensate drum V2 (FIG. 3) maintained at a pressure of about 5.1 p.s.i.a. Such condensate collects in the form of substantially salt free condensate. Alternatively, as shown by the dotted line L17 (FIG. 3) this condensate can be sent directly to the sprays 44 (FIG. 2), thereby insuring that the remaining condensate in condensate drum V2 is a high quality water suitable for use as substantially pure industrial water.

The now heated waste fluid in heat exchanger E1 (FIG. 3) exits from the heat exchanger E1 via line L18 into an evaporator EV1 where such heated waste fluid is vaporized at the first predetermined temperature T1 of about 186 F. and at a first predetermined pressure P1 of about 8.72 p.s.i.a. to form a vaporized portion VP1 (FIG. 3) of the waste water and to concentrate the corrosive salts in the residual waste fluid to form a concentrate C1 (FIG. 3) having about 1.96% by weight of corrosive salts. The concentrate C1 is refed via line L19 in a natural circulation loop back via line L16 to the heat exchanger E1. Another portion of the concentrate C1 is fed via line L20 to, for example, the tube side of a second heat exchanger E2.

Second stage The vaporized portion VP1 of the waste water (containing steam, ammonia and dissolved gases, such as CO H 8 and the like) exits from the first evaporator EV1 (FIG. 3) via line L21 to, for example, the shell side of the second heat exchanger E2. It will be understood by those skilled in the art that alternatively the line L21 (FIG. 3) may conduct the vaporized portion VP1 of the waste water to a condenser E4 and thence to the condensate drum V2 as shown by the dotted lines in FIG. 3. The second predetermined pressure P2 of about 5.1 p.s.i.a. in evaporator EV2 (FIG. 3) is lower than the first predetermined pressure P1 of about 8.72 p.s.i.a. in the In the second heat exchanger E2 (-FIG. 3), the vaporized portion VP1 of the waste water (carried by line L21, FIG. 3) at about 182 F. and about 8.7 p.s.i.a. heats the concentrate C1 of the waste fluid in heat exchange relationship at a second predetermined temperature T2 of about 162 F. at a pressure of about 5.1 p.s.i.a. in the heat exchanger E2. A line L22 conducts the heated concentrate'C1 (mixed with the second concentrate C2 from evaporator EV2 via line L23) at the temperature T2 of about 162 F. to the second evaporator EV2 where the heated mixture of the concentrates C1, C2 is vaporized at a second predetermined pressure P2 of about 5.1 p.s.i.a. and at the temperature T2 of about 162 F. to produce a second vaporized portion VP2 (FIG. 3) and to further concentrate the corrosive salts in the evaporator EV2 to form a second concentrate C2 having by weight about 3.8% corrosive salts.

In the natural circulation system associated with the heat exchanger E2 (FIG. 3) and the evaporator EV2, the line L23 (FIG. 3) conducts or recirculates the concentrate C2 back via the line L20 to the heat exchanger E2. The vaporized portion VP2 (FIG. 3) in evaporator EV2 exits from the evaporator EV2 via line L24 to a third heat exchanger E3. A line L25 (FIG. 3) conducts a condensed portion of the second vaporized portion VP2 from the heat exchanger E2 (FIG. 3) to the condensate drum V2 where it collects as substantially salt-free condensate. As shown in FIG. 3, equalizer line L3 6 maintains the pressure in condensate drum V2 at the same pressure as that in evaporator EV2.

A pump PIA (FIG. 3) pumps the concentrate C2 from the second evaporator EV2 via line L26 to an evaporator crystallizer EV3 of the type, for example, known as a Krystal crystallizer. Such evaporator crystallizer EV3 is manufactured by Struthers-Wells Corporation, Warren, Pa. The evaporators EV1 and EV2 are of the type, for example, manufactured by Swenson-Walker Corporation, Whiting, Ind.

Third stage The vaporized portion VP2 in line L24 (FIG. 3) is at a temperature of about 162 F. and at a pressure of about 5.1 p.s.i.a. A portion of concentrate C3 in evaporator crystallizer EV3 is pumped by a pump P2a through a line L27 (FIG. 3, in the forced circulation system having restrictive orifice 71 in line L28 and associated with the heat exchanger E3 and the crystallizing evaporator EV3) and into, for example, the tube side of the heat exchanger B3. In the heat exchanger E3, the concentrate C3 is heated by condensation of the second vaporized portion VP2, which portion VP2 is fed from line L24 (FIG. 3) to, for example, the shell side of the heat exchanger E3. The concentrate C3 is heated to about 132 F. at a pressure corresponding to the vapor pressure of the third concentrate C3 in evaporator EV3. It will be understood that in order to suppress vaporization and prevent subsequent crystallization of the third concentrate C3 in heat exchanger E3, the restrictive orifice 71 produces a higher pressure in heat exchanger E3 than the pressure P3 in evaporator EV3. A return line L28 (FIG. 3) from the heat exchanger E3 returns the heated concentrate C3 to the evaporator crystallizer EV3, where such heated concentrate C3 is vaporized at a third predetermined pressure P3 of about 1.35 p.s.i.a. and at a temperature T3 of about 124 F. to produce a third vaporized portion VP3 and to further concentrate the corrosive salts to form a third concentrate C3 that is a saturated solution S3 of about 39.1% by weight of corrosive salts. A condensate line L29 (FIG. 3) from heat exchanger E3 conducts the condensate from the second vaporized portion VP2 to the condensate drum V2.

The vaporized third portion VP3 from the evaporator crystallizer EV3 exits via line L30 (FIG. 3) to the condenser E4 where such third vaporized portion VP3 is condensed and conducted by line L31 to the condensate drum V2. Depending on the elevation of the condenser E4 above condensate drum V2, a pump (not shown) may be required to transfer the condensate from vaporized third portion VP3.

The corrosive salt removing loop shown in the lower right-hand portion of FIG. 3 has a line L32 in which a pump P5a conducts the saturated solution S3 of the corrosive salts through a filter F1 where the concentrated or saturated solution S3 containing about 25% solid salt crystals is filtered. The filtered liquid from the filter F1 is conducted by a line L33 to a tank T1 and pumped back by a pump P3a through line L34 to the evaporator crystallizer EV3. The salt crystals in the filter F1 containing about 7.5% water are discharged via line L33a (FIG. 3) from the filter F1 onto a conveyor 70, which conveyor 70 transports them to a solid disposal station (not shown).

Alternatively, as shown by the dotted line L32 in FIG. 3, the pump PSa may pump the saturated solution S3 in line L32 (FIG. 3) into a salt solution storage tank 72 for storage preparatory to its release to loading facilities (not shown) and ultimate disposal or further processing into salt products.

The substantially salt free condensate collected in condensate drum V2 (FIG. 3) is pumped by a pump P4a via line L35 to the distillation tower 46 (FIG. 3) where ammonia, carbon dioxide, hydrogen sulfide, benzene, or the like are removed from such condensate. The now substantially salt free condensate is fed via line L8 (FIGS. 2, 3) to the spray 44 (FIG. 2) of the continuous rotary quencher 32, shown in FIG. 2, or to other batch type coke quenching operations. The water product from this process may be made suitable for use as industrial pure water, such as boiler feed water or the like by diverting the condensate in dotted line L17 (FIG. 3) away from condensate drums V2.

The material balance of the above described apparatus 64 (FIG. 3) is shown in Table II below.

TABLE IL-MA'IERIAL BALANCE Approximate flow Stream Approximate steam analysis, wt. Number Lbs/hr. G.p.m. percent L7 450, 000 900 98.67% water, 1.33% salts. L14 160,300 Steam from quenching 3,550 ton per day of coke. L20 306,600 617 98.04% water, 1.96% salts. L21 143,400 Steam. L26 157, 800 316 96.20% water, 3.80% salts. L 150,800 Steam. L28 29,000,000 50,000 60.9% water, 39.1% salts plus crystals.

6, 450 Salt crystals plus 7.5% water. 18,150 31 60.9% water, 39.1% salts plus crystals; 36 1,980 Steam. L35 604,300 1, 240 Water (very low salt content). L30 151, 800 Steam. L12 150 Coke breeze (fluid containing coke particles).

ALTERNATIVE EMBODIMENTS It will be understood by those skilled in the art that alternatively as shown in the apparatus 64 of FIG. 4, the high temperature steam from the continuous rotary quencher 32 may exit from the hood 56 via steam line L9 into heat exchanbe E1. The contaminated waste fluid or water from the separator tanks 26 (FIG. 1) enters the first evaporator E1 via line L7 A pump P111 pumps such waste fluid through line L40 into the heat exchanger E1 where the steam at a temperature T of about 400 F. and at a pressure P0 of about 14.1 p.s.i.a. raises the waste fluid to a temperature of about 225 F. A line L41 conducts the now heated waste fluid back to the first evaporator EV1 where, at the temperature T1 of about 186 F. and at a pressure P1 of about 8.72 p.s.i.a., the first stage of the vaporizing cycle is performed.

Alternatively, evaporator EV1 can be integrated with heat exchanger E1 to use the waste steam from either a continuous coke quencher 32 or a batch type quenching apparatus (not shown).

BACKWARD FL'OW SYSTEM Two Stage FIG. shows a further alternative embodiment, an apparatus 64 involving backward flow of the waste fluid through such apparatus 64 In FIG. 5, waste fluid at a temperature of about enters evaporator EVl via line L7 from liquid extraction tower 68 (FIG. 3). Vaporized portion VP2 from evaporator EV2 at a second pressure P2 of about 3.4 p.s.i.a. and a second temperature T2 of about 146 F. is conducted by a line L51 from evaporator EV2 to, for example, the shell side of the heat exchanger E1 The waste fluid is conducted from evaporator EV1 (FIG. 5) via line L52 to, for example, the tube side of the heat exchanger E1 where such waste fluid is heated by the vaporized portion VP2 from line L51 at a temperature T1 of about 113 F. so that when a line L53 conducts such heated waste fluid from heat exchanger E1 back to the evaporator EV1 such waste fluid is vap0rized at such first temperature T1 of about 113 F. and at a first pressure P1 of about 1.35 p.s.i.a. The first vaporized portion VP1 from the waste fluid in evaporator EV1 is conducted by a line L54 to the condenser E4 for condensation to substntially salt free condensate. A pump Plzz conducts the concentrate C1 formed in evaporator EV1 (FIG. 5) via line L55 to the second evaporator EV2 The condensate from the second vaporized portion Vl2 in the heat exchanger E1 is conducted by a line L56 (FIG. 5) through a steam trap STl to the condensate drum V2 (not shown in FIG. 5).

Such concentrate C2 (FIG. 5) is conducted by a line L57 to, for example, the tube side of the second heat exchanger F2 The third vaporized portion VP3 from the evaporator crystallizer EV3 (FIG. 5) moves (at a temperature T3 of about F. and a pressure P3 of about 5.4 p.s.i.a.) via a line L58 to, for example, the shell side of the second heat exchanger E2 where the concentrate C2 is heated at a temperature T2 of about 146 F. Line L59 conducts the heated concentrate C2 back to the second evaporator EV2 In the evaporator EVZ (FIG. 5), the first concentrate C1 mixes with the concentrate in the second evaporator EV2 Such mixture forms the second concentrate C2 and is fed by a line L57 (FIG. 5) to the heat exchanger E2 'Such mixture is then heated in heat exchanger E2 and vaporizes at a second pressure P2 of about 3.4 p.s.i.a. and at the second temperature T2 of about 146 F. in the evaporator EV2 to form the second vaporized portion VP2 The second vaporized portion VP2 (FIG. 5) may be conducted by the solid line L51 in FIG. 5 as heretofore described to, for example, the shell side of the first heat exchanger E1 or as shown by the dotted line L51 (FIG. 5) to the condenser E4 and thence to the condensate drum V2 shown in FIG. 3. As in the prior cases, the condensate from the heat exchanger E2 is fed via a line L60 (FIG. 5 through a steam trap S12 to the condensate drum V2 shown in FIG. 3.

Third stage A pump P211 conducts the second concentrate C2 via line L61 (FIG. 5) to the evaporator crystallizer -EV3 Steam at about 200 F. from steam line L10 (FIGS. 2, 3, 5) and at a pressure of about 13.8 p.s.i.a. is fed via such steam line L10 from the rotary continuous quencher 32 (FIG. 3) into, for example, the shell side of the third heat exchanger E3 .A pump P3a (FIG. 5) pumps the concentrate in the evaporator crystallizer C3 (formed in the evaporator EV3 by the mixture of concentrate C2 and the concentrate in the evaporator EV3 in the evaporator crystallizer EV3 via a line L62 (FIG. 5) into, for example, the tube side of the third heat exchanger E3 where such third concentrate C3 is raised to a temperature of about 187 F. and re-enters the evaporator crystallizer EV3 by line L63 from heat exchanger E3 In the evaporator crystallizer EV3 (FIG. 5), the third concentrate C3 mixes with the second concentrate C2 and the mixture is vaporized at a temperature T3 of about 180 F. and at a pressure P3 of about 5.3 p.s.i.a. to form either the saturated solution S3 of corrosive salts or the third concentrate C3 and also to form the third vaporized portion VP3 which vaporized portion VP3 is conducted by the line L58 to the heat exchanger E2 The saturated solution disposal loop shown in theiower I: I left-hand portion of FIG. 5 is essentially the same 'a's'that shown in the lower right-hand portion of FIG. 3.

Alternatively, as shown in FIG. 5, the waste fluid can can be fed directly via line L to line L58 (when the third evaporator -EV3 is not in operation or employed). In FIG. 3, alternatively the waste fluid can be fed by dotted line L7 directly to the first evaporator -EV1; I

the first concentrate can be fed via line L to thesecond evaporator EV2; and the second concentrate C2 can be fed via line L26 to line L27.

Alternatively, the apparatus and method of this invention can be employed with a batch type coking apparatus by the use of steam accumulator (not shown).

Alternatively, other evaporators may be employed havmg: (a) the heating medium separated from the evaporating liquid by tubular heating surfaces (FIGS. 1-5); (b) the heating medium confined by 'coils, jackets, double walls, flat plates, and the like.

Usable evaporator types are as follows:

(f) long tube vertical with separated entrainment outlet;

(g) recirculating long tube vertical; (h) falling film;

(i) horizontal tube evaporator; and (j) wiped film.

SUMMARY OF THE ACHIEVEMENTS OFTl-IE OBJECTS OF THE INVENTION.

It will be recognized by those skilled in the art that the objects of this invention have been achieved by providing an improved (frontward and backward flow) apparatus 64 (FIG. 3), 64 (FIG. '4), and 64 (FIG. 5) for a method of purifying waste fluid (containing waste water and corrosive salts) with waste steam from a continuous coke quenching apparatus 32 or batch type coke quenching apparatus not shown) to produce substantially saltfree condensate, which improved apparatus 64,,(FIGS. 3-5), etc. and method utilize the heretoforewasted steam from a continuous coke quenchingapparatus 32 to produce the salt free condensate; produce a substantially salt free condensate for use in boilers or as coke quenching fluid; eliminate the corrosive atmosphere polluting eflluent produced in coke quenching operations by the use ofcon taminated waste fluid from the coke producing operation as a coke quenching fluid; eliminate suspended tar particles from the waste fluid; eliminate benzene, tar acids, tar bases, and oil from the waste fluid; eliminate CO ,-NH H 'S, benzene, and the like from the Waste fluid; aridiliminate corrosive salts from the waste fluid.

While in accordance with the patent statutes, preferred and alternative embodiments of this inventionhave been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

We claim:

1. A method of purifying waste fluid containing waste water and corrosive salts produced ina coke producing apparatus and normally utilized to quench coke in a coke quenching apparatus, with waste steam from said coke quenching apparatus to produce substantially salt free condensate, said method comprising the steps of;

(a) heating said waste fluid in heat exchange relationship with said steam to a first predetermined temperature at a firstpredetermined pressure;

(b) condensing said waste steam to form substantially salt free condensate;

" (c) vaporizing said heated waste fluid at said first predetermined temperature at said first predetermined pressure to vaporize a portion of said waste fluid and to concentrate the corrosive salts to form a con- "'centrate;

(1) said first predetermined pressure being lower than the pressure of said waste steam from said coke quenching apparatus;

(d) condensing said heated vaporized portion of said waste fluid to form substantially salt free condensate; and

(e) applying said substantially salt free condensate to said coke in said coke quenching apparatus to quench said coke thereby eliminating the disposal of said waste fluid and the contamination of the atmosphere with said waste fluid if said waste fluid were employed to quench said coke in said coke quenching apparatus and utilizing said waste steam for a useful. purpose. I

2. Themethod recited in claim lincluding the step of concentrating said corrosive salts to form a saturated solution of said corrosive salts.

3. The method recited in claim 2 including the step of crystallizing said saturated solution of said corrosive salts.

4. .The method recited in claim 1 including the steps of:

Y (a) heating said concentrate of residual waste fluid in hear exchange relationship with said vaporized portion of said waste fluid at a second predetermined temperature at a second predetermined pressure;

- (b) condensing said heated vaporized portion of said waste fluid to form substantially salt free condensate;

(c) vaporizing said heated concentrate of residual waste, fluid at a second predetermined pressure to vaporize a second portion of said heated vaporized portion and to further concentrate the corrosive salts' insaid concentrate to form a second concen- "trate; e

(1) ,said second predetermined pressure being lower than said first predetermined pressure;

and

(d) condensing said second heated vaporized portion to form substantially salt free condensate.

5. The method recited in claim 4 including the step of further concentrating said corrosive salts in said second concentrate to form a further saturated solution of said corrosive salts.

6. The method recited in claim 5 including the step of crystallizing said further saturated solution of said corrosive salts.

.7. The method recited in claim 4 including the steps of: (a) heating said second concentrate in heat exchange relationship with said second vaporized portion to a third predetermined temperature at a pressure which is higher than a third predetermined pressure; (b) condensing said second heated vaporized portion m to form substantially salt free condensate.

(c) vaporizing said second heated concentrate at said third predetermined pressure to vaporize a third port ion of said second heated concentrate and to further concentrate the corrosive salts in said second concentrate to form a third concentrate of said corrosive salts;

(1) said third predetermined pressure being lower than said second predetermined pressure; and

(d) condensing said third heated vaporized portion to form substantially sal-t free condensate.

= 8. The method recited in claim 7 including the step of concentrating said third concentrate to form a saturated solution.

1 1' 9. The method recited in claim 8 including the step of crystallizing said saturated solution of said corrosive salts. 10. The method recited in claim 1 including the prior step of settling out suspended tars in said waste fluid.

11. The method recited in claim 1 including the prior step of contacting said waste fluid with either light oil or benzene to remove tar particles suspended as droplets in said waste fluid.

12. The method recited in claim 1 including the prior step of extracting phenol, tar acids and tar bases from said waste fluid. t

13. The method recited in claim 1 including the step of distilling ofl? benzene, CO H 5, and NH from said heated vaporized portion to form a substantially pure condensate. I

References Cited UNITED STATES PATENTS 2,189,083 2/1940 Renkin 1594 VM 2,330,221 9/1943 Kcrmer 159-17 R 3,248,181 4/1966 Akimoto 159'45 3,299,942 1/ 1967 Iacoby l5917 R 1,888,465 11/1932 Miller 201-30 X 2,775,541 12/1956 Karl 20314 X NORMAN YUDKOFF, Primary Examiner D. EDWARDS, Assistant Examiner US. Cl. X.R.

15 l59-17 VS, 47, 4 VM; 202174; 20314, 48, 71, 88 

